RU2288076C2 - Tube working method and apparatus for performing the same - Google Patents

Abstract

FIELD: working metals by cutting, working tube blanks for lowering their wall thickness difference before rolling, finishing non-rigid tubes.

SUBSTANCE: method comprises steps of working outer surface of rotating tube whose one end is fastened in floating chuck of front drive center of machine tool. Said tube is placed onto mandrel arranged in front of cutting tool and moving simultaneously with it along axis of worked article. Blade type tool is used for working in order to enhance working efficiency. Position of worked part in radial direction is stabilized by means of hold-down rollers. Apparatus for performing the method includes front drive center with floating chuck and unit that may move along guides in direction of forming dimensions and on which in one plane normal to axis of worked tube cutting tool and mandrel are mounted. In plane of mounting cutting tool such as blade type tool and mandrel, hold-down rollers are mounted in addition.

EFFECT: enhanced efficiency of working.

2 cl, 3 dwg

Description

The invention relates to the processing of metals by cutting and can be used in the processing of pipe billets to reduce their difference in size before rolling, as well as for finishing operations of processing parts of the class of non-rigid pipes.

One of the main criteria determining the quality of pipes is tolerances for lateral pipe spacing, the requirement on which may be limited to 5-10% or less of the pipe wall thickness.

When rolling seamless pipes in one or another combination, the following general technological operations are used:

- preparation of the workpiece for production;

- pipe rolling;

- drawing of pipes;

- combined method (rolling and drawing);

- heat treatment of finished and intermediate pipes;

- chemical treatment of finished and intermediate pipes;

- finish;

- control of finished products.

Preparation of the workpiece for production is carried out by flashing-forming a hole in the ingot or round billet. At this stage, when using cost-effective tools and equipment, the real, the achieved difference in the workpiece exceeds 15% or more of the wall thickness. With further pipe rolling operations, there is a persistent preservation of this proportion of the pipe wall thickness, the so-called effect of technological heredity. Correction of this defect in the last stages of the technological process is expensive, especially with thin-walled pipes and, as a rule, is performed by machining.

A known method of grinding pipes, including fixing one end of the pipe on the outer surface in a floating chuck, while the pipe on the inner surface is based on a mandrel that is placed opposite the grinding zone and moves synchronously with the grinding wheel along the axis of the workpiece (RF patent No. 2145275, IPC B 24 V 5/04) - prototype. When implementing the method in the grinding process, uneven cutting of the metal along the perimeter occurs, more where the wall thickness of the pipe being processed is greater, and accordingly smaller where the wall thickness of the pipe is less. Thus, the initial difference in the processed pipe is reduced or completely eliminated.

The disadvantage of this method is:

- low productivity

- the instability of the obtained dimensions during processing, the reason for which is the rapid wear of the grinding wheel,

- contamination of the outer surface of the part with abrasive particles, which in turn requires the introduction of additional process steps to remove them in the case of ultrasonic testing.

A device for surface treatment of pipe billets is known, comprising a tool rigidly connected to each other for processing the outer surface of the workpiece and a deforming element mounted inside the workpiece in the processing zone on the cantilever holder coaxially with the workpiece, as well as a longitudinal feed drive, an tool for processing the outer surface the workpiece is made in the form of an abrasive wheel, and the device is equipped with a floating cartridge designed for fastening in it by one end of the workpiece (patent F №2150365, IPC 24 5/04, 2000) - a prototype.

During processing, the resulting pipe wall thickness is determined by the distance between the working surface of the grinding wheel and the surface of the deforming element, which completely eliminates the influence of such factors as ovality, eccentricity and curvature of the pipe axis on the thickness of its wall.

A disadvantage of the known device is:

- quick wear of the grinding wheel, which requires constant correction of its installation, this is due to stops the cutting process, measuring the machined size and adjusting the position of the working tool,

- low productivity

- the use of a tool that causes contamination of the outer surface of the part with abrasive particles.

The objective of the invention is the creation of a high-performance method of machining the outer surface of the pipe and device for its implementation, which would ensure stable processing of pipe wall thickness during the processing without reinstalling the tool position during processing of the given surface, eliminating contamination of the workpiece surface with abrasive particles.

The invention consists in a method of machining pipes, including processing the outer surface fixed at one end in a floating cartridge of the front driving center of the machine of a rotating pipe placed on a mandrel, which is located opposite the cutting tool and synchronously moves along it along the axis of the workpiece, the processing is performed with a blade tool, wherein the position of the part in the radial direction is stabilized by pressure rollers.

The invention also consists in a device for machining pipes, comprising a front driving center with a floating chuck and a unit that can be moved along the guides in the direction of size formation, on which, in one plane, perpendicular to the axis of the pipe being machined, a cutting tool and a mandrel are mounted, as cutting tools using a blade tool, and in the plane of placement of the cutting tool and the mandrel additionally mounted pressure rollers.

The technical result obtained from the use of the invention is as follows:

- high performance since blade processing, for example turning, is much more productive than grinding, especially with large metal removal;

- stability of the resulting size, because the change in the geometric dimensions of the blade tools as a result of wear is many times less than that of grinding wheels;

- obtaining a treated surface of high quality and unpolluted by abrasive particles, which allows ultrasonic testing to be used without intermediate operations;

- increases the accuracy of processing as a result of increasing the rigidity of the system "machine tool-tool-tool-part" (AIDS);

- the use of pressure rollers dampens the vibrations that occur during turning and gives the AIDS system additional rigidity, which is especially important when machining parts of the non-rigid pipe class.

In Fig.1 presents a schematic diagram of the device, Fig.2 is a product mounted on a mandrel, Fig.3 is a section in the plane of placement of the cutting tool, mandrel and pressure rollers.

The device comprises a front driving center, with a floating cartridge 1 (Fig. 1), mounted in the spindle of the headstock 2 and a bracket 3, which is mounted on a support 4. A mandrel 5 is fixed on the bracket (Fig. 2 and 3), so that it the support roller 6 is located in the plane of placement of the cutter 7. In the same plane, the pressure rollers 8 of the pressure unit 9 are installed, the rollers are supplied and locked by the lever 10, and the pressure of the rollers is regulated by the springs 12.

The proposed method is implemented as follows. The tubular billet 11 is mounted on the mandrel 5 and fixed at one end in the floating cartridge 1, it is informed of the rotation and axial feed of the caliper 4, and when the feed is sent to the cutter 7, processing of the part begins. Processing modes are selected from the following intervals: cutting speed from 20 to 50 m / min, feed from 0.46 to 1.3 mm / rev. During the processing of the part, vibrations occur, the amplitude of which is decreased by the pressure rollers, the pressure of which is controlled by the tension of the springs 12. The rollers 8 are removed manually using the lever 10. The wall thickness of the processed tube part 11 is dimensioned to provide a rigid dimension between the cutting edge of the cutter 7 and the supporting surface the mandrel roller 6, as well as the fixing of the part by the rollers of the clamping unit 9. With this arrangement of the part, the influence of the main factors causing the difference in t rub (ovality, curvature of the axis of the tube billet and eccentric difference).

Claims (2)

1. A method of machining pipes, including processing the outer surface of a rotating pipe, fixed at one end in a floating cartridge of the front leading center of the machine and placed on a mandrel, which is located opposite the cutting tool and synchronously moves with it along the axis of the processed pipe, characterized in that the treatment is carried out blade tool, while the position of the pipe in the radial direction is stabilized by pressure rollers. 2. A device for machining pipes, comprising a front driving center with a floating chuck and a unit having the ability to move along the guides in the direction of size formation, on which, in one plane, perpendicular to the axis of the pipe being machined, a cutting tool and a mandrel are mounted, characterized in that As a cutting tool, a blade tool is used, and in the plane of placement of the cutting tool and the mandrel, pressure rollers are additionally mounted.

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